[procedure] current-process-milliseconds

[procedure] current-gc-milliseconds

[procedure] seconds

msec returns number of milliseconds since a system-dependent start time.
It's fixnum, so it may be wrap-around.
current-process-milliseconds and current-gc-milliseconds are
similar to msec but returns a time consumed by the current
process (user+system) or in gc of the current process, respectively.

seconds returns the current time in seconds, measured from
system-dependent epoch.